I'd use the spelling
Kerensa, because it looks a little more whole and doesn't remind me of credenza or concertina. However, I discovered and loved the name via idolising Time Team's Carenza
Lewis, so spelling it that way would have personal meaning.
Ellie and I have discussed it as a potential - must come back to it again.
Freya Kerensa?
Freya Carenza? Possibly a little too
Star Wars?

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